Supporting column



I May 1, 1951 J. c. CURTIS SUPPORTING COLUMN 2 Sheets-Sheet 2 FiledApril 21, 1944 0 0 6 a? WZM 7 7 $200220?) claim 5. (242 2215.

Patented May 1, i951 John-r13. Curtis, .Claremont, N. :assignor to JoyManufacturing Company, a corporation of Pennsylvania Application April21, 1944,, Serial No. 532,173

. 19 Claims. 1

,My invention relates to :supporting .columns,

and more particularly to means for delivering I liquid under ap-nessllreto :an extensible supportme column :of the hydraulically actuated :type,

and-tothezstnuctural iieatures :oisuch-a column.

Inlsettingup.assupportinglcolumnLitisdesirable i hat the operator .xbe:iree to .guide ithe abutment engaging members of the .zoolumn while(the lat- Iter, is ibeing extended by fluid .;delivered to it zunderpressure. Mter lthe:abutmentsurlaces havezbeen engaged and 'the columnis supported without the aid of alihe operator, the operator :may .then.do

"whatever :is necessary .to increase the abutment en agin pressure forholding :the column firmly ih'the desired :position. :To effect theextending T the zcolum-n into engagement with 1the abutment sn iacesthere :may :be provided a motor actuated epumpingmeans vvormeans forssubjecting a may @omiquid i110 pressure for forcing the :-1 atter"toisnistons which operate .to extend the column.

If *the pressureat which :the liquid is delivered to the pistons is :notsufiioient :to :hold :the column inrthe edesired p ition when :thelatter :is sub.-

ie ed 2 1 the l ds to be placed :upon .it, then some suitable manuallyactuated .means .may ;be

provided ifQr increasing the abutment engaging :pressure. When :the10011111111 ;'-is :held extended only by the .1-iquid {delivered to:.it, .it will :.be appreciated that any leakage of liquid from .the

C mn w uld permit the lett r tO CQ11 DSB-lun- .less additional 'sliguidwas supplied. jBy maint n ng a continuous c nnection Ebetween the motoractuated pumping means iand its supply :of in crating .fiuid. thepumping means :will oper- "ate and deliver liquid to :the column untilthe lat. ,r :can extend :nofurither tunderithe discharge pressure of:the vpumping means. :The pump in means will when stall, ihut,iaiS.SO0I1 as j liquid leaks from zthercolumn, :the pumping mean willautomaticallystart-againand pumDliquid-to the column :nntil the maximum:abutment engaging ---pr.e ssure-3isagaimreached. o'If-the-oolumnisforced my invention is to provide *improved means for.delivering fiuid underpressurekto aefiuidractuated .2 I x device. Afurther object of my invention is to provide an improved hydrauliccolumnhaving improved cneans for .automatically preventing collapse thereofdue to leakage. Yet another object of my invention is to provide animproved fluid actuated pump. These and other objects of the inventionwill'appear more fullyin the following descrip'tion.

"In the-accompanying drawings there arershown for purposes -ofillustration one form :and two modifications which the-inventionmayassume in practice.

In thesed-rawings:

Fig. 1 is a front elevational viewof an illustrative embodimentof myimproved supporting column.

Fig. '2 is a view in longitudinal vertical section taken through thesupporting column shown in Fig. l.

Fig. 3 is an enlarged vertical sectional :view showing a portionof thesupportin column and improved means for pumping liquid froma liquidstorage chamber to passages leading to fluid actuated pistons of thecolumn, the "view being taken-on :the plane of the line 3-3 of Fig. 1.

Fig. 4 is an-enlarged =vieWtaken-on the plane of theline--'4'4 of Fig.l-showingaportionof the supporting column in section and the remainderin plan.

-5 is -a fragmentary sectional view taken on the planeof "the line 5-5of Fig. 4 and show i-ng valve means for controlling the venting -offluid from the fluid actuated "pistons of the column to thestorage-chamber.

Fig. "6 is a-front elevational view'showing a-portion of a modified formof the invention.

Fig. *7 is an enlarged vertical sectional view taken on the plane of theline .1-'1 of Fig. '6. v

Fig. '8 is a verticalsectional view showing a modification of the fluidactuated pumpingmeans of the form of the inventiOnshOwninFigs. 1 to 5.

Inthe illustrative embodimentof theinvention shownin Figsll to 5,inclusive, the improvedsupporting column is generally designated l andcomprises .a body portion 2 having laterally spaced ,bores 3 and 4opening through its lower end, and a bore .5 located between ,the bpresf3 1 at its lower end, with a-reduced bore [0 opening into the bore 5 toform a chamber space 12 for containinga body of liguid, such asoil.-Recipro-' cable within the bores 8 and "4, respectively; are

3 pistons l4 and I5 carrying piston rods I6 and I! which extend throughbushings l8 attached, as by bolts IE], to the body portion 2, and thepiston rods have fixed to their lower ends abutment engaging members and2|.

Attached to the side of the body portion 2, as by bolts 23, is acylinder block 24 having stepped coaxial bores 25 and 26 communicatingwith each other at their adjacent ends. Reciprocable within the bores 25and 25 is a piston 28 having an enlarged head portion 29 fitting thebore 25 and a reduced head portion 33 fitting the bore 26. A passage 3|extends through the body portion 2 of the column and the cylinder block24 to connect the chamber space |2 in communication with the lower endof the bore 26, and a spring pressed ball valve 33 opens to permitliquid to flow through the passage 3| toward the bore 26 and closes toprevent flow in the opposite direction. A passage 34 opens into the bore26 at a point between the ends of the latter and communicates with thepassage 3 lat a point between the valve 33 and the chamber l2. Formed inthe reduced head portion 33 of the piston 28 is a passage 35 openingthrough the lower end of the head portion 38- and opening through theside of the latter at a point to communicate with the passage 34 justbefore the piston 28 reaches the lower end of its stroke. The lower endof the bore 26 is connected under the control of a spring pressed ballvalve 3'| with a passage 38 which communicates with branch passages 39and 40 opening, respectively, into the upper ends of the bores 3 and 4.It will be seen that when the position 28 is caused to re ciprocate, thehead portion 30 will operate to pump liquid from the chamber |2 to thebores 3 and 4. As soon as the bore 26 is connected to the chamber I2through the passages 34 and 35 the pumping stroke terminates and thepressure beneath the piston drops permitting the latter to be moved moreeasily to the lower end of its stroke.

a The upper end of the bore 25 is closed by a cylinder head 42, and aspring 43 acting between the lower side of the piston head portion 29and the cylinder block 24 at the lower end of the bore 25 normally holdsthe piston 28 against this cylinder head. The space at the lower end ofthe head portion 29 communicates continuously with the atmospherethrough a vent port 44. Formed within the cylinder headis a valvechamber 45 containing a piston type distributing valve 46 forcontrolling the supply of pressure fluid through a passage 48 to thecylinder bore 25 and for controlling the venting of fluid from the bore25 through a passage 58. The passage 48 opens into an enlarged portion5| of the valve chamber at a point to be covered by'one end of the valve46 when the latter is in one of its limiting positions, and a fluidsupply conduit 52 opens into the chamber portion 5| at such a point thatfluid supplied to the chamber must flow around a flange 54 on the valve43 in order to reach the passage 48. The end portion 55 of the valveadjacent the passage 48 is slightly reduced in cross section to presentan annular area 56 which is somewhat larger'than the area 51 at theopposite side of the flange 54. It will be seen that with the valve inits open position, as shown in Fig. 3, a flow of fluid through thechamber portion 5| toward the passage 48 will act on the flange 54 tourge the valve toward .its closed position and, if the flow of fluidbecomes great enough, the force acting on 4 the valve will be sufiicientto move the latter to its closed position. With the valve closed, thepressures at opposite sides of the flange 54 become equal, and thepressure acting against the larger area 56 tends to move the valve toits open position against the pressure acting on the area 51.. Theexhaust passage 53 opens into a chamber space 59 surrounding a reducedportion 68 of the valve 46, and the space 59 is connected, when thevalve is seated, past the outer end of the reduced portion 60 to anexhaust port 6| in the cylinder head. On the valve 46 at the inner endof the reduced portion 60 is an annular area 62 which is subjected tothe pressures in the bore 25 for opposing opening movements of the valveby the pressure acting on thearea 56. Opening through the wall of thecylinder bore 25 is an exhaust port 63 which is so located that it isuncovered by the side of the piston portion 29 shortly after the passage35 has been connected in communication with the passage 34.

The operation of the mechanism so far described is as follows: After thecolumn has been placed in the desired position, the operator connectsthe conduit 52 in communication with a pressure fluid supply, as byopening a suitable valve not shown. If. the valve 46 should be in itsclosed position, the fluid pressure builds up in the chamber portion 5|and acts against the valve area 56 to move the valve to its openposition for supplying fluid to the bore 25 through the passage 48 andfor cutting off the exhaust of fluid through the passage 58. Until thevalve opens, the area 62 is subjected only to atmospheric pressure andbut little resistance is offered to the opening movement of the valve.As soon as the valve opens, the end portion 55, as well as the area 56,is subjected to the pressure in the bore 25, and the valve is held openeven though the pressure in the bore acts on the area 62. The pressurefluid acts in the bore 25'against the top of the piston 28 and forcesthe latter downwardly against the action of the spring 43. Just beforethe piston reaches the-lower end of its stroke, the bore 26 is connectedthrough the passages 35 and 34 to the chamber l2, reducing the pressurewhich opposes the downward movement of the piston. The pressure in thebore 25 then forces the piston downwardly until the exhaust port 63 isuncovered and the bore 25 is freely vented to atmosphere. The reductionof the pressure in the bore 25 results in a rush of fluid through thevalve chamber portion 5|, and the action of this fluid on the valveflange 54 causes the valve 46 to be moved to a position covering thepassage 48 and opening the exhaust passage 58. The piston 28 is thenmoved upwardly by the spring 43 as the pressure fluid escapes from thebore 25 'through the exhaust passage. The escaping pressure fluid actson the area, 62 holding the valve closed against the force of the linepressure acting on the area 56. When the piston reaches its uppermostposition, the pressure acting on the area 62 reduces rapidly and thevalve 46 is unseated by the pressure acting on the area 56 to supplypressure fluid again to the bore 25. The reciprocation of the piston 28causes liquid to be pumped from the chamber l2 through the passage 3|,past the ball valve 33, through the bore '26, past the ball valve 31,through the passage 38 and the passages 39 and 43 to the bores 3 and 4where it acts on the pistons I4 and I5 and effects an extension of thecolumn until the abutment engaging members 8,

essence 2D and 2| are firmly in engagement With-abut 'ments. The supplyof pressure fluid through the conduit "52 is maintained while the columnis in use, so that the pump will automatically introduce more fluid intothe cylinders 3, 4, whenever there is any leakage such as to reduce thepres-' sur' 'tnerein.

when it isdesired to lo'wer the eomm'n, the supply of fluid through theconduit 52 is interrupted and 'a valve 65, as shown in Fig. 5, ismanually adjusted to connect a passage 66, leading from the "passage 38,in communication with a passage 61 opening into the chamber i2 In Figs.6 and 7 there is shown a modification of the invention in which a,manually operated pump, generally designated 1, is provided 'for pumpingliquid from the chamber ['2 through the passages 31 and 38 to the bores3 and 4. v The pump 1!] comprises a cylinder member "H fitting Within "abore 12 in a cylinder block 13 attached 'to the side of the body portion2 of the column I and having a bore 14 "containing a piston 15. Thepassages 3| and 38 communicate with the bore M under the control of thespring pressed ball valves '33 land. 31, respectively. The upper end ofthe piston is pivotally connected at Hi to an operating lever 11, andtheoperating lever is lpivotally connected, at a point spacedlongitudinally of the latter from the point 55, to one end of a link 18which is pivotally connected at its other end to a collar 86 clamped, asshown in Fig. 7, "between a flange 3| on the cylinder member II and acollar 82 threaded on the cylinder member.

in order to obtain a rapidextension of the olumn, there is provided aconduit 83 opening into the chamber i2 above the surface of the liquidtherein and adapted to be connected by amanually operated valve 8-4 to apressure fluid supply. -,In setting up the column, the valve 84 isopened to supply pressure fluid to the chamber I2 for forcingliquid fromthe latter through the passages 3| and 33 to the bore 3 and 4. After theabutments have been engaged by the members B, and 2:, the valve 84 isclosed and the pump lever T! is operated to actuate "the piston 15 forforcing a little more liquid to 'the bores 3 and 4 andefiecting a, verypowerful engagement of the abutments.

Fig. -8s-hows a fluid actuated pump similar to thatof Fig. 3, but inthis case the piston 28 is provided with a portion BBbetween the headportions -2'9 and and fitting a bore 85 which is somewhat larger thanthe bore 26 butis smaller than the bore 25. Aconduit 88 suppliespressure fluid to a passage 89 opening into the lower end of the bore86, and this pressure fluid acts on an annular area 8? on the pistonportion 85 for yieldingly urging the piston toward the cylinder head-42.The distributing valve 46' controls the flow-of pressure fluid relativeto the bore 25 for e'fiecti-ng, in the same manner as that describedinthe first form of theinvention, the reciproca tion of piston 28. Inthis case the distributing valve has a reduced portion 90 which issomewhat smallerthan the openings! connectingthe space 59 with theexhaust port 6|. At the outer end of the-portion 90 is an enlargedportion 92 which moves into the opening 9| with just enough clearance toprovide a restricted openin to exhaus t when the valve is in its, closedposition. l'ay appropriately selecting the area of the portion92relative to the area ofjthe face 93 'on'the body of thevalve, asubstantial holding s rcerer keeping the valve seated can be provided,while at the same time a clean-cut opening movement of the valve may 'beinsured because as the valve opens an increased venting passage area "isprovided at its left hand end as the portion 92 moves out'of the opening9| and the smaller portion -90 extends through the opening.

As a result of "my invention, it will be noted that'there is provided animprovedfiuid 'actuated supporting column having improved means fordelivering to the column, a fluid under pressure. While the column shownherein is extended by an incompressible fluid, it will be understoodthat the fluid delivery means associated with the column is adapted foruse in the delivery of a gaseous fluid. It will be noted that byreason'of theprov'ision of the fluid delivery means, the operator isfree to support the column in the desired position as it is "extendedinto engagement with extraneous abutments. With the pressure generatingmeans operating automatically to compensateior any pressure drop in-thesupport ing'column, it will be seen that the pressure 'will bemaintained and the column will not collapse because v of the leakage offluid therefrom. A rapid extension of the column is obtained by thesubjection of the body "of liquid to a continuous pressure, and, iffurther extension is neededunder increased pressure, such extension "maybe quickly "obtained by manually actuated 'means Because of theprovision of a plurality of abutment engaging member's-at one end'of thecolumn, these members beingactuated by separate'pis'tons to which fluidis delivered from a common source, there Will be an automatic adjustmentof "the members to compensate 'for unevenness in "the abutment surface.

While there are in this application "specifically described one form andtwo modifications which the invention may assume in practice, it will beunderstood that "these are "shown for purposes of illustration and thatthe invention may be further modified and embodied in various'oth'eriorms Without departing from its spirit or the scope-of theappended "claims.

Wh'at'I claim as new and desire to secure 'by Letters Patent is:

1. In a'fsupporting column, in combination, a body meinberhavingparallel, offset bores Opening through opposite ends thereof, a tubularshaped member fixed at one end withinoneof said bores and having ranabutment engaging member at its outer end, a piston reciprocable withinanother of saidbores and'ca'rrying'a piston rod to the'outer end ofwhich an abutment engaging member is attached, said tubular "memoercooperating with said body'memb'erto form a liquid storage space, andmeans "for delivering liquid under pressure from said storage space tosaid piston ffor effectingrelativemovement of said abutment "engagingmembers into engagement with extraneous abutments.

2, In a supporting column, in combination, 'a body member having acentrally located bore opening through one 'end thereof, a -tubularshaped memb'erfixed atone end Within'said'bore andp'rojecting from saidbody member, an abut me'ntfengaging member attached to the outer end ofsaid tubular member, a plurality'of'bores opening through the oppositeend of said body member and arranged in parallelism with said centrallylocated bore and spacedequi-distantly from the latter at the oppositesidesof said body member, pistons reciprocable Within said'plurab ityof'bore's"fa'nde'ach carrying a piston rod to the outer "endof "which"an abutmentenga'ging member is attached, said tubular membercooperating with said body member to form a liquid storage space, andmeans for delivering liquid under pressure from said liquid storagespace to said pistons for effecting relative movement of said abutmentengaging members into engagement with'extraneous abutments.

3. In a supporting column, in combination, a body member having acentrally located bore opening through one end thereof, a tubular shapedmemberfixed at one end within said bore and projecting from said bodymember, an abutment engaging member attached to the outer end of saidtubular member, a pair of bores opening through the opposite end of saidbody member at points spaced equidistantly from opposite sides oftheaxis of said first mentioned bore in parallelism with the latter,pistons reciprocable within said pair of bores and each carrying apiston rod to the outer end of which an abutment engaging member isattached, said tubular member cooperating with said body member to forma liquid storage space, and means for delivering liquid under pressurefrom said liquid storage space to said pistons for effecting relativemovement of said abutment engagingmem bers into engagement withextraneous abutments; said last mentioned means including'common passagemeans communicating with said pair of bores. U W Y 4. An extensiblecolumn comprising, in com bination, a member providing a bore, a pistonreciprocable in said bore for varying the length of said column, meansfor delivering fluid under pressure to said piston for effecting anextension of the column, said last mentioned means including steppedcylinder bores opening into each other, a piston having portionsreciprocable in each of said cylinder bores, one of said piston portionsacting as a pump piston and the other acting as a motor piston, valvemeans for controlling the supply of operating fluid to said motorpiston, means for yieldingly opposing movement of said motor piston bythe operating fluid supplied thereto, means for venting fluid from saidmotor piston at the end of the working stroke of the latter, fluidsupply and discharge passages for conducting fluid relative to said pumppiston, inlet and discharge valves for controlling the flow of fluidthrough said supply and discharge passages, and passage means forconnecting the working end of said pump piston to said fluid supplypassage at the supply side of said inlet valve shortly before the end ofthe pumping stroke is reached.

5. An extensible column comprising, in combination, a member providing abore, a piston reciprocable in said bore for varying the length of saidcolumn, means for delivering fluid under pressure to said piston foreffecting an extension of the column, said last mentioned meansincluding stepped'cylinder bores opening into each other, a pistonhaving portions reciprocable in each of saidcylinder bores, one of saidpiston portions acting as a pump piston and the other acting as a motorpiston, valve means for controlling the supply of operating fluid tosaid motor piston, cans for yieldingly opposing movement of said motorpiston by the operating fluid supplied thereto, means for venting fluidfrom said motor piston at the end of the working stroke of the latter,fluid supply and discharge passages for conducting fluid relative tosaid pump piston, inlet and discharge valves for con trolling the flowof fluid through said supply and discharge passages, and means forventing the space at the working end of said pump piston shortly beforeoperating fluid is vented from said motor piston.

6. In a supporting column, in combination, a body member having boresopening through opposite ends thereof, a tubular shaped member fixedwithin one of said bores and having an abutment engaging member at itsouter end, a piston reciprocable within anotheiz of said bores andcarrying a piston rod to the-outer end of which an abutment engagingmember is attached, said tubular member cooperating with said bodymember to form a liquid storage space, means for delivering liquid underpressure from said storage space to said piston for effecting relativemovement of said abutment engaging members into engagement withextraneous abutments, said last mentioned means including a cylinderbore containing a reciprocable piston, valve controlled passage meansconnecting said cylinder bore in communication with said liquid storagespace and with said first mentioned piston, means for effectingreciprocation of said last mentioned piston, and means for subjectingthe surface of the liquid in said storage space to the action of apressu'r'dfluid.

7. A pump, mechanism comprising, in combination, means providing acylinder bore, a piston reciprocable in said cylinder bore, means for'yieldingly urging said piston toward one end of said bore, means forsupplying operating fluid to one end of said piston for forcing thelatter through working strokes against the action of said yieldingmeans, means for venting operating fluid from said piston at the end ofits working strokes, valve controlled supply and discharge passages forconducting fluid to be pumped relative to an area at the opposite end ofsaid opposite end of said piston, and means for venting fluid from saidpiston areashortly before the end of the working stroke of said pistonis reached.

8. A pump mechanism comprising, in combination, means providing steppedcylinder bores opening into each other, a piston having portionsreciprocable in each of said bores, means including a valve forcontrolling the supply of operating fluid to one of said pistonportions, means for yieldingly opposing movement of said piston by theoperating fluid supplied thereto, means for venting operating fluid fromsaid piston after a predetermined movement of the latter, fluid supplyand discharge passages for conducting fluid to be pumped relative to theother of said piston portions, inlet and discharge valves forcontrolling the flow of fluid through said supply and dischargepassages, and means for venting fluid from the other of said pistonportions shortly before operating fluid is vented from the first of saidpiston portions.

9. A pump mechanism comprising, in combination, means providing steppedcylinder bores opening into each other, a piston having portionsreciprocable in each of said bores, means including a valve forcontrolling the supply of operating fluid to one of said pistonportions, means for yieldingly opposing movement of said piston by theoperating fluid supplied thereto, means for venting operating fluid fromsaid piston after a predetermined movement of the latter, fluid supplyand discharge passages for conducting fluid to be pumped relative to theother of said piston portions, inlet and discharge valves forcontrolling the flow of fluid through said supply and dischargepassages, means for venting fluid from the erating. fluid. is ventedfrom the first of. said. pis.--

ton portions, said last mentioned means including'aventpassageiopeninginto thebore contain ing the other of said. piston. portions, andpassage means: extending through theother of said piston portions: and:communicating. with. said vent passage shortly before the end of the.pumping strokeof; said. piston.

101.. A. pump mechanism comprising, in combination, means providing.stepped cylinder bores opening into each other, a piston having portionsreciprocable in each. of said bores, means includingra: valve; forcontrolling the supply of operatingi fluid. to the largerone of. saidpiston portions, means for yieldingi-y opposing movement of. said pistonby the. operating fluid Supplied thereto, means for venting operatingfluid. from said larger piston. portion after a predetermined movement.ofythe. latter, fluid; supply and discharge passages for. conductingfluid to be pumped rela tiveto the smaller of ;said. piston: portions,inlet and discharge valves for controlling. the flow of fluid. throughsaid supply and discharge passages, and; means: for venting fluid. fromthe smaller of said piston portions shortly before operating fluid isvented from the. larger one of said piston piston by the operating fluidsupplied theretomeans for venting operating fluid from said largerpiston portion after a predetermined movement of the latter, fluid.supply and dis charge; passages for conducting; fluid to be pumpedrelative to the smaller of said piston portions, inlet and dischargevalves for controlling the. flow of fluid through said supply anddischarge. passages, means for venting fluid. from the smaller of saidpiston portionsshortly before operating fluid is vented from the largerone of said piston portions, said last mentioned venting means includinga vent passage opening into the smaller 0t said cylinder bores betweenthe ends of the: latter, and passage means in said smallerpistonpo-rtion adapted to communicate with said vent passage before theend of the working. stroke of said piston is reached. I

12. A pump mechanism comprising, in com bination, means providing threecoaxial cylinder bores decreasing progressively in diameter, the middleone of said bores opening into the other two, a piston having portionsreciprocable in each of said bores, means including: a valve for. con-'means for venting fluid from the smaller one of said piston portionsshortly before operating fluid is vented from the larger one of saidpiston portions.

13. A pump. mechanism comprising, in. combination, means; providing avcylinder bore, a. piston reciprocable insaid cylinder bore, valve meansfor controlling the supply of? operating fluid to and the. exhaust offluid from said cylinder boreat one end of said. piston, said valvemeans movable to its. exhaust effecting position on the venting ofoperating fluid. from said bore, means for venting operating: fluidfrom: said bore at the end of. the. working stroke of said piston, meansfor yieldingly opposing movement. of said piston by the: operatingfluid, valve controlled. supply and discharge passages for conductingfluid to, be

pumped relative to an area at the opposite. end of said piston,,and.means for venting fluid. from said piston area shortly before the end.of the. working, stroke of said piston is reached.

145A pump mechanismv comprising, in com.-'

bination, means providing steppedcylinder bores opening into. eachother, a piston having portions. reciprocable in each. of said bores,valve means: for controlling the supply of operating fluid to andt'theexhaust of fluid from one of said bores, said valve. means movable to.its exhaust effect.- ingpositionl on the venting of operating fluid fromsaid bore, meansfor venting operating. fluid fromv said here after apredetermined. movement of said piston in its. working stroke, meanssupplying pressure fluid to another of said bores for opposing; movementof said pi'stonby the operating' fluid. supplied thereto, fluid supplyand dis:- charge passages for conducting fluid to be pumped relative toanother of said bores. inlet.

and: discharge. valves. for; controlling the. flow of fluid; throughsaid supply and discharge passages,-

and. means. for venting fluid from the. last. mentioned oneof said boresshortly before operating fluid is vented. from the. first mentioned oneof said bores. i

15:. In a supporting column, in combination, a lower frame, an elongateduprightv support secured: to. said frame. midway between the sides ofthe latter and" having a roof engaging member at: its upper end, a pairof extensible hydraulic cylinder and piston devices secured to frame andarranged in parallelism with said elongated support and spacedequi-distantly therefrom. at. opposite sides of said frame, saidcylinder and piston devices having foot pieces thereon below said frameand engageable with the floor. a liquid. pump carried by said frameintermediate. said devices and in adjacency tov the: lower end of saidsupport, and valve controlled passage means in said frame between thecylinders: of said devices and having connection with said pump betweensaid cylinders for supplying liquid under pressure concurrently to saiddevices to extend the latter to bring said foot pieces'firmly intoengagement with the floor even when the latter is. uneven.

16-. In a supporting column, in combination, a; lower frame, anelongated upright supportase cured to said frame midway between thesides of the latter and having a roof engaging member at its upper end,a pair of extensiblehydraulic cylinder and piston devices secured tosaid frame and arranged in parallelism with said elongated support andspaced equi-distantly therefrom at opposite sides of said frame with theupper ends of said devices extending upwardly relative to the lower endof said support and with the lower ends of said devices near. the bottomof raid frame, said cylinder and piston devices having foot piecesthereon below said frame and engageable with the floor, a liquid soacarried by said frame intermediate said devices and in adjacency to thelower end of said support, and valve controlled passage means in saidframe between the cylinders of said devices and having connections withsaid pump between said cylinders for supplying liquid under pressureconcurrently to said devices to extend the latter to bring said footpieces firmly into engagement with the floor even when the latter isuneven.

17. In a hydraulic mine column, a pair of parallel extensible cylinderand piston devices respectively having floor engaging abutments, a crossconnecting frame extending between and secured to said devices, a columnelement supported by said cross frame midway between said paralleldevices and extending vertically above said cross frame, said columnelement having a roof engaging abutment, a source of liquid underpressure on said cross frame, passages in said cross frame forconnecting said liquid source to the cylinders of said devices, andmeans on said cross frame for effecting liquid flow from said sourcethrough said passages to the cylinders of said devices whereby thepistons of said devices may be concurrently subjected to the action ofhydraulic pressure to extend said devices to bring about, with thecolumn element vertical, firm engagement of said floor engaging abutmentwith the floor, whether the latter is level, uneven or sloping, andalso'firm engagement of said roof engaging abutment with the roof,whereby said column may be fixed in vertical position, and said liquidflow effecting means embodying means operative to effect trappin ofliquid in the cylinders of said devices'to hold the latter firmly inadjusted position thereby to secure the column in place between the roofand floor.

1 18. In a hydraulic mine column, a centrally located vertical columnelement having a roof en,- gaging abutment and a base providing a crossframe, a pair of extensible cylinder and piston devices arranged inparallelism on said base at the opposite sides of said cross frame andspaced equidistantly from said centrally located column element, saiddevices respectively having floor engaging abutments, a source of liquidunder pressure on said base, passages in said cross frame for connectingsaid liquid source to the cylinders of said devices, and means foreffecting flow of liquid under pressure from said source through saidpassages to the cylinders of said devices for concurrently subjectingthe pistons of said devices to the action of hydraulic pressure toextend said devices to bring about, with the column element vertical,firm engagement of said floor engaging abutments with the floor, whetherthe latter is level, uneven or sloping, and also firm engagement of saidroof engaging abutment with the roof, whereby said column may be fixedin vertical position, and said liquid flow effecting means embodyingmeans operative 'to effect trapping of liquid in the cylinders of saiddevices.

12 to hold the latter firmly in adjusted position thereby to secure thecolumn in place between the roof and floor.

19. In an extensible hydraulic supporting'column, a bottom frame havinga transverse portion, a vertical column element secured centrally tosaid transverse frame portion and extending upwardly and provided at itsupper end with a roof engaging abutment, a pair of cylinder and pistondevices carried at the sides of said transverse frame portion andarranged in parallel relation and spaced equidistantly from said columnelement, said devices having floor engaging abutments at their lowerends, a liquid reservoir carried by said bottom frame, a pump on saidbottom frame, passages in said transverse frame portion for connectingsaid pump to said reservoir and to the cylinders of said devices, andmeans for effecting flow of liquid from said pump through said passagesto the cylinders of said devices concurrently to extend the latter tobring about,'with the column element vertical, firm engagement of saidfloor engaging abutments with' the'floor, whether the latter is level,uneven or sloping, and also firm engagement of said roof engagingabutment with the roof, whereby said column may be fixed in verticalposition, and said flow effecting means being operative to effecttrapping of liquid in the cylinders to hold firmly said devices inadjusted position thereby to secure the column in place between the roofand floor.

JOHN C. CURTIS.

REFERENCES CITED UNITED STATES PATENTS Number Name 1 Date 170,419 WalshNov. 23, 1875 333,077 Ingersoll Dec. 22, 1885 552,274 Cole Dec. 31, 1895771,057 Gay Sept. 27, 1904 1,032,993 Cordell July 16, 1912 1,035,376McWane Aug. 13, 19 2 1,085,691 Lavers Feb. 3, 1914 1 ,212,757 FreeseJan. 16, 1917 1,654,673 Barks Jan. 3, 1928 1,657,070 Cumner Jan. 24,1928 1,699,194 Junkers Jan. 15, 929 1,903,887 Widener Apr. 18, 19331,920,285 Wilkins et al Aug. 1, 1933 2,163,959 Nilson June 27,19392,270,233 Shaw Jan. 20, 1942 2,343,993 Naylor Mar. 14, 1944 2,346,678Hair et al Apr. 18, 1944 FOREIGN PATENTS Number Country Date 392,618Great Britain of 1933 441,872 Great Britain of 1936 475,390 GreatBritain of 1937

